Tak Epsilon 130

[Allinthehead]

Hi all, i was just wondering if anyone has any opinions on this scope.

I was thinking of it as an upgrade to a William Optics Star 71. I realise it will produce diffraction spikes, personally i like them.

From reading various opinions online they seem to hold collimation well. The plan was to use my Asi 1600 and Asi 071 with it.

Is it asking for trouble or should i stick to a refractor. I could have an fsq 85 for similar money. 

Richard.

[henry b]

GREAT SCOPE, HOWEVER COMPLICATED IN A NUMBER OF WAYS BUT WILL PRODUCE EXCELENT IMAGES. IF IMAGING TIME IS LIMITED THEN STICK TO THE REFRACTOR FOR CONSISTANCY.  henry b..........

[ollypenrice]

It is, perhaps, dallying with trouble rather than asking for it outright!  I have a larger Epsilon visit regularly in the hands of a very experienced imager and he did take a while to get it tickled up. It's very impressive now, though.

The spikes would bother me a bit on such a widefield instrument because there really can be a lot of them...

Then, after all that tilt-tweaking and collimating, you'll need to take it apart to clean it some day. If you're a happy tinkerer you won't mind. If you're not, you probably will! I dislike tinkering so this would not be the scope for me but I can see why others love it.

Olly

[Allinthehead]

6 hours ago, henry b said:

GREAT SCOPE, HOWEVER COMPLICATED IN A NUMBER OF WAYS BUT WILL PRODUCE EXCELENT IMAGES. IF IMAGING TIME IS LIMITED THEN STICK TO THE REFRACTOR FOR CONSISTANCY.  henry b..........

Thanks Henry. Appreciate that.

15 minutes ago, ollypenrice said:

Then, after all that tilt-tweaking and collimating, you'll need to take it apart to clean it some day

Thanks Olly. That's a comprehensive reply i appreciate that. How often would it need cleaning do you know?

[ollypenrice]

1 hour ago, Allinthehead said:

Thanks Henry. Appreciate that.

Thanks Olly. That's a comprehensive reply i appreciate that. How often would it need cleaning do you know?

That very much depends on local environment. Dust isn't a problem and is best ignored. There are pollen-related organic contaminants which might be best removed regularly though. My answer is that I don't know.

Olly

[Allinthehead]

47 minutes ago, ollypenrice said:

That very much depends on local environment. Dust isn't a problem and is best ignored. There are pollen-related organic contaminants which might be best removed regularly though. My answer is that I don't know.

Olly

I think i could live with once every 2/3 years, any more often than that would be a real pain. Thanks for your input as cleaning wasn't something i had considered. 

[Ikonnikov]

I went for the E130D over the FSQ85 due to its speed and image circle (plus a number of reports of faulty FSQ85s at the time); it requires patience to get right (as described in my PM) but is capable of great images. The easy option in this price range would be another refractor, maybe an Esprit 100ED or possibly the 120ED with the 0.75x Riccardi reducer if you want something in the same ballpark focal length wise (although both are somewhat longer than the E130D), but with the right collimation tools the Epsilon should be eminently doable (especially with your OSC camera). And the Skywatchers aren't nearly as cute!

I cleaned the mirrors for the first time a couple of months ago (about 6 months short of its third birthday) as I noticed a lot of muck on the secondary and was starting to get radial artifacts around brighter stars. I think it only got so bad as I'd left it with the camera off near a tree while making adjustments a few times, the primary wasn't that bad though.

 

Paul

[Allinthehead]

17 hours ago, Ikonnikov said:

I went for the E130D over the FSQ85 due to its speed and image circle (plus a number of reports of faulty FSQ85s at the time); it requires patience to get right (as described in my PM) but is capable of great images. The easy option in this price range would be another refractor, maybe an Esprit 100ED or possibly the 120ED with the 0.75x Riccardi reducer if you want something in the same ballpark focal length wise (although both are somewhat longer than the E130D), but with the right collimation tools the Epsilon should be eminently doable (especially with your OSC camera). And the Skywatchers aren't nearly as cute!

I cleaned the mirrors for the first time a couple of months ago (about 6 months short of its third birthday) as I noticed a lot of muck on the secondary and was starting to get radial artifacts around brighter stars. I think it only got so bad as I'd left it with the camera off near a tree while making adjustments a few times, the primary wasn't that bad though.

 

Paul

Thanks Paul.

once in 2/3 years for cleaning is fine with me. I have the option of having the collimation confirmed prior to shipping so hopefully the only tweaking i need to do will be spacing/tilt and my camera has a tilt adjuster built in (which can be adjusted while the camera is connected to scope) so that should help. Is the spacing the same as spacing would be when using a reducer, in other words your camera dictates correct spacing?

[Ikonnikov]

Corrector to chip distance quoted by Takahashi is 56mm to which you need to add 1/3 the thickness of any glass in the optical path (filters/optical window of CCD) which will be another around 1-2mm. Then subtract camera backfocus (specified by manufacturer) from this and the remaining distance needs to be made up by spacers/filterwheels OAG etc depending on what you want/need in the imaging train.

Although it is mechanically better to have a single machined spacer to fit with the other components, in practice it's difficult to predict/measure the exact length of all the other parts down to the precision required (you need to be within 0.1 to 0.2 mm for a properly corrected field) so I would recommend components with a slightly shorter length than calculated and making up the distance e.g. with M54, M48 and/or M42 spacing rings (which will require some trial and error, I bought a selection from Teleskop Service). If you have enough space then a variable M48 adaptor would be ideal. You might even be able to fine-tune your spacing using the tilting plate on you camera without bothering with spacers.

Paul

[Allinthehead]

That's great thanks. I like your thinking with the tilt adjuster.

Richard.